The present invention concerns a device and a method for monitoring the quality of a fuel stored in a fuel tank.
In modern diesel vehicles, the injection system, and here in particular the high-pressure injection pump, must be lubricated by the diesel fuel. If said systems run dry only locally, as a rule an immediate failure is the result. Repair costs of several thousand euros must then be reckoned with.
Such failures occur if diesel is contaminated with gasoline by incorrect refueling, for example. Because the fuel dispensing pistols for gasoline have a smaller diameter than the fuel dispensing pistols for diesel, such an operating error at the fuel station cannot be prevented. Damage to the injection system, however, does not requires said worst operating mistake. The more power a diesel engine draws from the same engine displacement, the more the injection system requires the fueled diesel to correspond exactly to the specification. The corresponding tolerances are narrower with every new generation of engines. Already a small contamination of the diesel fuel with water or other substances can lead to greatly increased wear or even to an immediate failure of the injection system.
Said problem is occurring more frequently since high end injection systems are also being operated in countries in which the development of the infrastructure for the fuel supply has not kept in step with the development of the injection systems.
Methods are known from WO 2007 084 406 A2 and from WO 1999 048 846 A1 with which the quality of a fuel can be measured by means of infrared spectroscopy. It is a disadvantage that said methods require a complicated and bulky optical design, so that they are not practical for use in vehicles.